Differential Regulation of RGS-2 by Constant and Oscillating PTH Concentrations

PTH has diverse effects on bone metabolism: anabolic when given intermittently, catabolic when given continuously. The cellular mechanisms underlying the varying target cell response are not clear yet. PTH induces RGS-2, a member of the Regulator of G-protein Signaling protein family, via cAMP/PKA, and inactivates PKC-mediated signaling. To investigate intracellular signaling pathways with different PTH concentration-time patterns, we treated UMR 106-01 osteoblast-like cells in a perfusion system. PTH was administered intermittently (4 min/h, 10⁻⁷ M) or continuously at an equivalent cumulative dose (6.6 × 10⁻⁹ M). cAMP was measured using radioimmunoassay, mRNA levels using real-time rtPCR and ribonuclease protection assay, and protein levels using Western immunoblotting. A single PTH pulse transiently increased cAMP levels by 2000% ± 1200%. In contrast to continuous PTH exposure, cAMP induction remained unchanged with intermittent PTH, ruling out desensitization of the PTH receptor. In continuously perfused cells, RGS-2 abundance was three to five times higher than in cells intermittently exposed to PTH for up to 12 h. MKP-1 and -3 were significantly less induced with pulsatile PTH; exposure-mode-dependent differences in MMP-13 and IGFBP-5 were small. Pulsatile but not continuous PTH administration prevents PTHrP receptor desensitization and accumulation of RGS-2 in osteoblasts, which should preserve PKC-dependent signaling.     

Late Dissection of Pulmonary Autograft Treated by Valve-Sparing Aortic Root Replacement

Abstract   Dissection of the pulmonary autograft is an extremely rare complication requiring emergent treatment as there is a chance of rupture and proximal aortic involvement. The autograft dissection can involve the aortic annulus, causing separation of leaflets from the annulus in addition to causing annular dilatation, thereby precluding resuspension of leaflets. The usual treatment in such cases is to perform the Bentall procedure, which involves placing a valved conduit (usually mechanical valve) and thereby necessitating anticoagulation. This report describes a case of successful valve-sparing aortic root replacement following the Ross procedure with dissection of autograft.     

Patients with moderate-to-severe psoriasis recapture clinical response during re-treatment with etanercept

Background  Patients with psoriasis experience remission and gradual reappearance of erythematous and scaly plaques and require individualized treatment over time. A goal of psoriasis treatment is to provide optimal efficacy with a flexible therapeutic regimen that may include treatment pauses.
Objectives  To determine whether patients receiving initial treatment with etanercept who then pause therapy would subsequently recapture response during re-treatment.
Patients and methods  A post-hoc analysis of 226 patients with moderate-to-severe psoriasis from a large multicentre trial was performed. Patients had received etanercept 50 mg twice weekly subcutaneously until a target clinical response had been achieved, then had paused treatment and eventually relapsed. They were then re-treated with etanercept 25 mg twice weekly. The number of patients recapturing a Physician Global Assessment (PGA) of psoriasis rating of ≤ 2 (clear, almost clear or mild) on first re-treatment was assessed. Patient satisfaction during the initial treatment and first re-treatment period was also determined.
Results  A total of 187 (83%) patients recaptured the target clinical response of a PGA of ≤ 2 after re-treatment. The majority of patients [219 of 226 (97%)] reported satisfaction with etanercept re-treatment. No new safety concerns emerged during re-treatment.
Conclusions  In this post-hoc analysis, patients with psoriasis who were re-treated with etanercept 25 mg twice weekly effectively recaptured clinical responses that patients found satisfactory. A flexible treatment option is available to dermatologists and patients for individualized care.